Individual image processing techniques are prolific, as taught in “Numerical Recipes in C,” and as available in software packages such as Photoshop™. Some image processors make use of correlators that compare a reference image to a scene to find a reference object in the scene. Some correlators are discussed in “Optical Processing” by A. VanderLugt.
There is prior art on the theory of correlators, on the design of the optical processor assembly of optical correlators, and especially on the theory of designing the reference image filters of the correlator. There is little prior art on practical applications of correlators, and there is little art on the integration of correlators and supporting image processing techniques along with other components, processes, and methods to provide practical solutions for real-world problems, especially those applications that require real-time object or pattern recognition or tracking. A typical scientific paper on a correlator describes a spot of light, or a three-dimensional plot of the spot, and does not solve any real problem. The large literature on reference filter design addresses optimization of a variety of internal correlator functions, such as light efficiency, but fails to address any optimization in terms of the application of the correlator.
Anthony VanderLugt teaches the operation of a correlator. He also teaches the potential of post-processing of the correlation plane. J. Horner teaches the combination of one specific preprocessor and a correlator. None of these sources combine pre-processing, correlation, and post processing, and none describe how to integrate all these functions with other functions necessary to provide a practical, real-time capability for pattern recognition, tracking of objects and trends, and outputs for control of external resources such as camera gimbals.
Many practical applications of an image recognition capability require a continuous tracking of the location of the recognition, for example, in a missile seeker tracking a target aircraft. The prior art does not disclose a combination of pre-processor, correlator, and post-processor in conjunction with a location tracker. In many applications, the correlation filter must vary with the circumstances of the application. For example, in a missile engagement, an image of a target grows as the missile gets closer to the target, and may also change due to changes in aspect as the target, or missile, maneuvers. Prior art fails to disclose techniques for efficiently modifying correlation filters, or selecting alternate filters, to provide for correlation with the image of a target as it changes in aspect angle, scale, or both.
In prior art descriptions, there is little discussion of means of controlling and synchronizing all operations of various processing components of a system. For example, use of a Windows™ operating system is insufficient for many practical missions as Windows™ does not provide deterministic timing and synchronization necessary for real-time operation of recognition and tracking systems employing correlators.